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NASA C*'INTRACTOR REPORT 177340 STUDY FOR PREDICTION OF ROTOR/ WAKE/FUSELAGE INTERFERENCE PART II: PROGRAM USERS GUIDE (llASA-CB-I"/?3_0-Vol.2) $TODI FO_ PRZDZCTION OF ROTOR/MAKE/FUSELAGE INTSHFE_ENCE. PART 2: PROG_AB USERS GUIDE Final _epoLt, I Jun. 1980 - I Mov. 1983 (Analytical Bethods, Inc., _edmcnd, bash.) 9_ F HC AO5/HF R01 D. R. Clark B. Maskew G3/U 1 H85-22347 Uncla s _U170 CONTRACT NAS2- 10620 NoVember 1983 _'"- .% _ '7\\ k .'2_2_/,.,: :.7t . .<._.t https://ntrs.nasa.gov/search.jsp?R=19850014037 2020-04-19T21:09:53+00:00Z

:.7t - NASA · theory, the reader is referred to the original reports., The discussion here will place the rotor elements in the basic frame-work provided by VSAERO and will concentrate

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  • NASA C*'INTRACTOR REPORT 177340

    STUDY FOR PREDICTION OF ROTOR/

    WAKE/FUSELAGE INTERFERENCEPART II: PROGRAM USERS GUIDE

    (llASA-CB-I"/?3_0-Vol.2) $TODI FO_ PRZDZCTIONOF ROTOR/MAKE/FUSELAGE INTSHFE_ENCE. PART

    2: PROG_AB USERS GUIDE Final _epoLt, I

    Jun. 1980 - I Mov. 1983 (Analytical Bethods,Inc., _edmcnd, bash.) 9_ F HC AO5/HF R01

    D. R. Clark

    B. Maskew

    G3/U 1

    H85-22347

    Uncla s

    _U170

    CONTRACT NAS2- 10620NoVember 1983

    _'"- . % _ '7\\

    k .'2_2_/,.,: :.7t

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    NASA CONTRACTOR REPORT 177340

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    STUDY FOR PREDICTION OF ROTOR/WAKE

    FUSELAGE INTERFERENCE

    PART II: PROGRAM USERS GUIDE

    D. R. Clark

    B. Maskew

    Analytlcal Methods, Inc.

    2047 - 152nd Avenue, N.E.

    Redmond, WA 98052

    Prepared for

    Ames Research Center

    under Contract NAS2-10620

    ,_4nl_onalAeronautics and

    ,Space Administration

    Ames Research CenterMoffett Field. California 94035

  • TABLE OF CONTENTS

    section

    LIST OF FIGURES .....................

    1.0 INTRODUCTION ...................

    2.0 GENERAL PROGRAM ARRANGEMENT .............

    3.0 PANEL _ODEL DEFINITION (Card Sets 9 through 16)

    3.1 Body Panelling

    3.1.1 Conventional Input .3.1.2BodiesofRevolution3.1.3 Lifting Surfaces--Type-3 Patches ....3.1.4 Rotors--Type-4 Patches .........

    4.0 WAKE INPUT

    4.2 Separation Line Specification. Card Sets 9through 23 ...............

    4.2.1 Wake Definition for Type-1 Wakes ....4.2.2 Wake Definition for Type-4 Wakes on

    Bodies .................

    4.2.3 Wake Definition for Type-4 Wakes onRotors .................

    5.0 ROTOR BLADE ELEMENT MODEL INPUT DESCRIPTION ....

    5.1 Rotor Patch Identifiers (Cards R1 and R2) • • •

    5.2 Output Print Controls ...........5.3 Iteration Controls (Card 14) .........

    5.3.1 Blade Flapping . . . • .........5.3.2 Rotor Lift ...............

    5.3.3 Rotor Moments .............

    5.4 The Blade Element Model Geometry (Card Sets R6,R7, RS, R9 and RI0) ..............

    iii

    i

    2

    513

    1824

    30

    30

    33

    42

    45

    51

    51

    5152

    5253

    53

    53

  • TABLE OF CONTENTS (CONCLUDED)

    5.5 Rotor Performance and Control (Cards Rll, R12,R13 and R14) ................. 55

    5.5.1 Rotor Speed and Flapping (Card Rll) . . 55

    5.5.2 Rotor Blade Cyclic Control (Card R12).. 555.5.3 Rotor Loads and Moments (Cards RI3 and

    RI4) ................. 565.5.4 Airfoil Data Sets (Card RIS, Card Sets

    R16) .................. 56

    6.0 INPUT DATA DECK BLOCKING AND VARIABLE LIST ..... 57

    6.1 Input Summary ................. 57

    6.2 Input Variable List . . . . . . ...... 586.3 Rotor Input Data Deck Description _ ...... 65

    7.0 REFERENCES ...................... 73

    APPENDIX : Sample Case

    (a) Input

    (b) Output (Abridged)

    II

    iv

  • LIST OF FIGURES

    o

    1

    2

    3

    5

    6

    7

    9

    i0

    2i te

    General Program Schematic .........

    Rotor Calculation Schematic ........

    3

    4

    Conventional Body Input

    (a) Patch-Section-Point Breakdown .......(b) Typical Input Data Set ..........

    67

    Typical Wing Panelling

    (a) Point Input and Tip Closure Schematic . • •

    (b) Typical Wing Input ............

    Sample--Body of Revolution--Nacelle

    (a) Patch Section Points Schematic .......

    (b) Nacelle Input List ............

    9

    10

    14

    15

    Simple Elliptical Fairing

    (a) Basic Set-up ...............

    (b) Input Data Listing ............

    1617

    Sample Lifting Surfaces

    (a) Simple Tail--Schematic .....

    (c) More Complicated Tail--Schematic

    (d) More Complicated Tail Input Details ....

    20

    2122

    23

    Main Rotor Modelling

    (a) Schematic.b) Input Details _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

    2526

    Tail Rotor Modelling

    (a) Schematic .................

    (b) Input Details ...............

    Wake-Grid-Plane Definition

    28

    29

    (a) Simple Isolated Rotor ...........(b) Embedded Body ...............

    31

    32

    iii

  • LIST OF FIGURES (CONCLUDED)

    _o

    11

    12

    13

    14

    15

    16

    17

    18

    Title _o

    Type-i Wake-Wing Separation Lines ..... 34

    Wake Trajectory Definition ........ 36

    Wake Shedding Schematic--Multi-line Input . 38

    Multiple Patch Wakes ........... 41

    (a) Type-4 Wake on Nacelle • • • 43cb,Type-_separat,dwakeonBio_k_d_lo_

    Rotor Head ................ 44

    Rotor Wake Specification--Simple IsolatedRotor ................... 46

    Rotor Wake Input Schematic with FuselagePresent . ................ 49

    Rotor Blade Element Model--Schematic • • • 54

    iv

  • 1.0 INTRODUCTION

    Because the body/rotor program is a direct development of

    Program VSAERO (Ref. 1), no attempt will be made here to describein detail the set-up and operation of these features of the

    present analysis which are in common with the original program.For the description of the non-rotor components, the developmentof the panelling schemes and the discussion of the undez_lying

    theory, the reader is referred to the original reports., The

    discussion here will place the rotor elements in the basic frame-work provided by VSAERO and will concentrate on a description of

    how rotary wing aircraft may be built up and placed in spaceusing the flexibility inherent in the program geometry routines.

    The body/rotor code outlined here is directly related to the

    1000-panel version of Program VSAERO delivered to the NASA AmesResearch Center and installed on the C_AY computer. The computa-

    tion times are consistent with those published in the o_iginal

    Program User's Guide for cases with complicated wakes if allow-ance is made for the rotor calculation by multiplying by a factor

    of roughly 1.3.

    1

  • 2.0 GENERALPROGRAMARRANGEMENT

    The rotor analysis is contained in a subroutine of programVSAERO and is called whenever a component is identified as

    belonging to a type 4-patch. Since the rotor blade element

    analysis responds to changes in inflow velocity, the rotor calcu-lation is placed within the wake relaxation loop structure. This

    is highlighted in the solution block diagram in Figure I. A

    typical solution would proceed as follows.

    A. From input data, program assembles body and rotor panelmodel.

    B. Program forms surface panel influence coefficients.

    C. Initial wake shape is constructed.

    Do On first pass, program sets up blade element model, andassuming uniform inflow, calculates rotor loads and mo-ments and (if requested) trims rotor. On subsequent

    iterations, inflow calculated on previous cycle is used.From calculated loadings, program evaluates rotor disc

    flow through velocities (local momentum balance) and

    doublet strength (to feed the rotor wake) and passesthese back to the panel model.

    E. Solve for body panel singularity strengths.

    F. Calculate new wake shape and determine new inflow veloc-

    ities at rotor panel centers.

    G. Return to D to complete wake relaxation cycle.

    He If requested, carry out viscous/potential flow iteration

    re-entering at D.

    I. Termination.

    Embedded within the rotor performance module are nested

    loops which control the blade flapping, rotor thrust (with col-lective pitch change) and rotor moments (with cyclic pitch

    change). These are outlined in the rotor calculation block

    diagram in Figure 2. At each azimuth location, the section loadsare calculated for every station out along the blade. These are

    integrated radially to form the azimuthal totals. The blade isthen moved to the next azimuthal location with flapping motions

    in response to any out of balance at the first position added.

    The blade is cycled around the azimuth until blade flapping hasstabilised. The thrust is checked against the desired level and

    the collective pitch adjusted. Once the required thrust has beenachieved, rotor moment trim _s checked and adjusted if required.

    2

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  • 3.0 PANEL MODEL DEFINITION (Card Sets 9 through 16)

    3.1 Body Panellinu

    3.1.1 Conventional Input

    Body panelling, including any lifting components w_. _

    present, follows exactly the format set down in the Progr:VSAERO User's Guide, Ref. i. As a result, the body can be maa_

    up of any convenient combination of panels, patches and com-ponents. In the VSAERO hierarchy, the panel is the smallestelement controllable by the user. A patch is a collection of

    panels in a regular array and a component is an identified groupof patches taken together for the evaluation of force and moment

    totals. Components may be further grouped into assemblies.

    The body shape may be entered in several ways, depending on

    its complexity and on the way in which the shape data is avail-able. Conventionally, the body is defined with a set of loft

    lines which are generally cut at constant body locations, station

    (x), buttline (y) and waterline (z). Figure 3 illustrates how a

    typical body may be first broken into patchesgFigure 3 (a), andthen inputr Figure 3(b). The patch allocation is made so that

    the different regions of the body may be represented by panelling

    of the appropriate density, high in regions of particular in-terest, low in other areas bearing in mind that within a patch,

    the panels form a regular array with the same number of panels ineach row and column. Consequently, patch boundaries almost al-

    ways occur where large changes in body cross section are present

    and in regions where, away from areas of interest, panel densi-

    ties are being reduced for reasons of economy.

    In the case of the body used in this illustration, the shape

    was defined with a series of station (constant x) cuts. fol-

    lowing the VSAERO User Document, Ref. i, each section is defined

    by a series of points located in a local axis system in the

    global coordinate system. The data set defining each sectioncontains a header card which contains the origin of the local

    axis system in the global coordinate system, the scale and orien-tation of the section (section may be scaled and/or rotated to

    ease input), and indicator cards which alert the computer to the

    way in which the data is being input and which indicate whetherthe section is internal to or closes a patch and provide informa-

    tion on how the patch is to be divided up. The header card is

    then followed by the string of points defining the section,

    together with node cards which alert the computer to the way inwhich the surface is subdivided, to any changes in surface curva-

    ture at junctions, and to the termination of the string.

    Program VSAERO offers the user great flexibility in the ways

    in which the shape may be input. Individual defining sections

    may be input in either the x (with y and z), y (with x and z), orz (with x and y) planes or in generalized x, y and z coordinates.

    Any other previously defined section may be automatically copied

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    or polar coordinate sections are available.

    The data sets for successive sections are stacked to form

    the input data set for a patch and the way in which they are

    stacked is of particular importance. Sections should be stackedin order and in a direction consistent with the way in which thepoints are input along each section. In the example shown in

    Figure 3, the _oints on each section were input up along theprofile on the stark _ard (positive y) side toward the top center-line and although the input points do not necessarily dictate

    panelling directly, the direction of input determines the order

    of the panel, with the first section input making up side 1 of apatch, and the panels numbered in the direction of the input

    points. Since program VSAERO requires that panels and patcheshave an anticlockwise corner point order when viewed from outsidewith the bottom to top input scheme used in Figure 3, the sec-

    tions must be stacked from front to rear. If the _ had been

    entered from top to bottom, then the section input order wouldhave been reversed and the patch would have been defined with

    sections input first at the rearmost edge of the patch and

    working forward.

    Input sections need not have the same number of defining

    points. However, when instructing the program on how the sectionshould be subdivided, it should be remembered that a patch is a

    regular array and all colun_ns must have the same number ofpanels. This is determined by the user properly setting the

    appropriate dividing instructions (the node cards) in the section

    input string.

    Wing sections are conventionally input as shown in Figure 4.

    Using the same format as outlined for bodies above and startingwith the lower trailing-edge point, the surface is input point bypoint working forward toward the leading edge, around the leading

    edge and aft over the upper surface. As with the body inputdescribed above, node cards are inserted to delineate regions of

    differing panel density or changes in surface curvature. For

    in3tance, in the example shown, the panelling is required to bemore dense close to the leading edge. This is achieved by in-

    serting a node card with a value of NODEC-I at the leading edge

    (indicating the end of a region but maintaining surface curva-

    ture) and using values of the distribution controls, INTC-2, atthe end of the lower surface and INTC-I at the end of the upper

    surface. Following this procedure, sections should be stacked

    from root to tip if only the starboard (positive y) side of thevehicle is being modelled.

    Although a panel is the basic element in modellng the sur-face and the solution proceeds with the strength of the sing_-

    larlty used to represent the panel as the unknown, the patch is

    the most conveniently manipulated unit. Patches may be construc-ted and moved into place to represent the configuration in any

    way convenient to the user. They may be ordered in any way

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  • without significantly affecting the solution and allow changes toa configuration to be made by removing a feature and simply

    plugging in one or more replacement patches to remodel thevehicle.

    Summarising, the input llst for a typical surface patchwould be as outlined below. The names used for the data items

    are those employed in the Program VSAERO User's Manual. The

    terms "chordwise" and "spanwise" can be considered to represent

    directions along the input section and along the patch lengthrespectively. For completeness, they are also defined here.

    IDENT Patch type 1-Wing2-Body

    3-Lifting Surface (Neumann)4-Rotor

    KOMPKASS

    Defines component and assembly to which

    patch belongs

    PNAME Patch title

    STX, STY, STZ

    SCALE, ALPHA, BETA

    INMODE

    NODES

    Section Cards:- (Stacked in spanwise direction) CARD ii

    Locanion of origin of section input points

    Scaling factor and rotation angles

    Type of section input

    Nodes to signal changes in spanwise paneldistribution, surface curvature, end of

    patch, etc.

    NPS Number of spanwise panels in the interval

    INTS Way in which spanwise section is divided

    Defininu Input Points:- _.v

    BX, BY, BZ Coordinates of section points.on INMODE used.

    Form depends

    11

  • . \

    Chordwise Nodes:- CARD 14

    NODEC Nodes to signal changes in chordwise distri-bution, surface curvature, end of section,etc.

    NPC Number of chordwise panels to be generated inin the interval

    INTC Way in which chordwise section is to bedivided

    The values of the nodes used to delineate changes in either

    chordwise (NODEC) or spanwise (NODES) directions are the same.In both cases, values of 1 and 2 represent the end of a regionwithin a patch where in the first case, surface curvature is

    continuous into the next region and in the secondcase is discon-tinuous. A value of 3 indicates the end of a section, chordwise,

    or a patch, spanwise, while values of 4 and 5, used only on the

    last sections of patches indicate, respectively, the final sec-

    tions of components and of the whole configuration.

    A similar arrangement with matching values is used to indi-

    cate the way in which the surface is to be divided in the

    chordwise and spanwise directions. The parameters, INTC and

    INTS: may be values of 0 through 3 depending on whether thepoints are to be:

    valueClosely spaced at the beginning and end of the region 0

    Closely spaced at the beginning of the region 1

    Closely spaced at the end of the region 2

    Equally spaced 3

    When an unequal dis=ribution is called for, the distance

    along the surface across the interval is bzoken up using a cosine

    form. A detailed description of the procedure is given in theProgram VSAERO Manual, Ref. i.

    Of course, the panelling could be built directly upon theinput points and sections with no subdivision or interpolation.

    In this case, the input points on successive sections are simplyconnected together to form the panelling. This option is selec-table by setting NPS or NPC equal to zero. Any values other than

    zero determine the number of panels within the particular span-wise or chordwise interval.

    12

  • In the discussion above, the standard method of inputting

    configurations has been outlined. Program VSAERO offers manyother options. Two of them, which are particularly useful in

    entering helicopter shapes, are outlined below.

    3.1.2 Bodies of Revolution

    There are many applications in the modelling of typical

    helicopter sha_es that do not require the detail provided bysection by sectlon input. Man_ configuration elements, in fact,may be simply defined as bod%es of revolution. Examples aEeengine nacelles, tail boom sections, rotor head fairings and

    external stores. Figures 5 and 6 illustrate how two of these, asimple engine nacelle and a rotor head fairing (or radome) may be

    generated.

    For the first example, Figure 5, the engine nacelle, the

    unit is made up of one section defined in the y - 0 plane byinputting values of x and z to outline the profile and then

    rotated through 3600 to form the nacelle. It can be modelled as

    one patch with four separate regions. They are: the inlet face,the inner surface of the inlet, the outside surface of the na-

    celle, and, finally, the exhaust plane.

    As with normal input, the card set describing the nacelle ispreceded by a patch card. Generally, only one section card is

    required. This locates the input section in the global coordi-nate system and specifies its orientation and scale relative tothat frame. The parameter, INMODE, describes how the section

    points are to be input; INMODE=2, for both the examples in

    Figures 5 and 6 signifies points being entered in the y - 0plane. If a flow-through nacelle _ere being modelled, INMODE=5

    could have been used to specify a standard NACA 4-digit crosssection.

    The body of rotation option is selected by setting the

    spanwise node card, NODES, to a negative value. For the ex-amples, simple polar symmetric bodies are used so NODES is -3 inboth cases. However, more complex bodies may be built up by

    combining sections to vary panel density, and in that case,values of -i o_ -2 would be appropriate at the intermediate

    spanwise sections depending on whether the surface curvature wascontinuous or discontinuous across the node. The final section,

    completing the rotation, would, of course, have NODES--3 signi-

    fying the closing of the patch (or -4 or -5 if this were the lastpatch on the component on the body).

    Definition of the cross-section points (defining the local

    chordal shape) follows the same rules for defining conventionalcross sections outlined above.

    13

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  • The input set is completed by specifying the final and

    initial angles, _,to define the rotation arc on CARD 15. For abody such as the nacelle, remote from the system plane of sym-

    metry, a full 3600 of rotation is used. However, in the same

    applications where the flow is symmetrical, where no yawing isinvolved and where the body is on the plane of symmetry, thenonly the positive side of the body of revolution is defined and

    is 180o.

    The second example used, the ellipsoidal fairing of Figure

    6, illustrates another feature of Program VSAERO; that is, theability to construct elements of the configuration as separate

    components in the most convenient orientation and then rotate

    them or move them to the required location. The positioning [email protected] a_e controlled by entries on a special component cardwhich must precede a patch or a group of patches identified as

    belonging to a separate component. This card precedes the firstpatch identifying card.

    In the simple example given the component is made up of onlyone patch. As with the nacelle, it is defined in the y - 0 planeby inputting the values of x and z outlining the cross section.

    This outline is then rotated about the section 'X' axis to form

    the body of revolution.

    Once the shape is formed in the section coordinate system,

    three further processes are available at the component levelbefore the final shape is set in the global frame. At this

    level, all the patches within the component may be scaled, eitherincreased or reduced in size, rotated or translated. The changes

    are applied in that order. Two rotations are available; a simple

    one, where the body is rotated about the component 'Y' axis androtation about a general axis that is deflned by two input

    points. The simple rotation is the d_fault mode. The user-

    defined axis rotation is entered by specifying a negative valuefor the scale parameter and then inserting an extra data cardwhich contains the rotation axis defining points. For the simple

    fairing case shown in Figure 6 the default is used and the bodyis pitched up 900 to lie with its long axis in the horizontalplane.

    3.1. _ Liftina Surfaces--Type-3 Patches

    A further option offered by Program VSAERO which isuseful in modelling components remote from a region of interest

    is the ability to use a _ifting-surface representation ratherthan a full surface singularity model, and enforcing the N_umannrather than the Dirichlet boundary condition. A typical applica-

    tion of this feature would be in modelling wings or other liftingor control surfaces that do not have a direct effect on the com-

    ponents that were the focus of the study or in regions where no

    18

  • B

    {

    aerodynamic rigor is sacrificed by not including the effects of

    the thickness of the components. Figure 7 shows examples of this

    where simple type-3 patches are used to model typicalvertical/horizontal tail assemblies.

    Depending on the level of detail required, this assemblycould be created by as few as two defining points on each of

    three sections if simple, flat surfaces are desired. The example

    in Figure 7(a) and (b) shows this input. The group of inputcards required is preceded by a patch card (and a component card

    if a separate component is called for) callin_ out a type-3patch. Input continues with the section card defining the lowerroot and then two cards defining the trailing- and leading-edge

    points followed by a chordwise node card. Note that on thechordwise node card the program is instructed to break the chord

    down into five panels, NPC-5, distributed so that they are denser

    at the leading edge, INTC-2.

    The second section card, at the joint between vertical and

    horizontal planes, with a spanwise node value, NODES, of twosignifying a discontinuity in surface curvature, Contains theinformation to divide the vertical section in the spanwise direc-

    tion into four rows of panels, NPS-4, spaced equally,

    INTSm3. Input is complete with the section defining the horizon-ual plane. In this case there are five panels spanwise, NPS-5,

    divided so that they are spaced densely at root and tip, INTS-0.Since this is the last section to be input on this patch, the

    spanwise node, NODES is set equal to three. The panelling in thechordwise direction is the same on the horizontal plane as in the

    vertical.

    In the second example, Figure 7(c) and (d), cambered sec-

    tions are used on both the vertical and horizontal sections and,

    consequently, a small transition piece is required to go from the

    vertical to horizontal planes. This is formed quite simply by

    allowing the program to correct th_ sections defining the top ofthe vertical panel and the root of the horizontal panel and

    generate a row of panels to fill the gap. To do this, foursections are required, The first section, as before, defines the

    root of the vertical panel this time using INMODE-I, points input

    as X and Y values, to define the section camber line. The sec-tion was defined relative to the quarter chord point; th_ values

    of STX, STY, and STZ locate the section in the global frame. In

    the example, the camber line distribution is assumed constant upthe panel and as a consequence, the top section is input bysimply relocating the root section with the appropriate values of

    INMODE-0, with the SCALE factor set to give the correct taper.

    The root section of the horizontal plane is again defined

    with input points, this time values of X and Z in a constant Yplane, INMODE-2, taking care to place it in the correct positionrelative to the earlier input sections using the appropriate STX,

    STY, and STZ local origin values. Again the tip section (thecamber is assumed constant) is input simply by copying and

    19

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  • scaling the root section. He_e, however, the section is pitched

    down using the pitch angle control, ALF, to model an appropriatevalue of section twist. Since both surfaces and the connecting

    fairing are being modelled as one patch, the chordwise distribu-

    tion of subdivided panels must be conserved. This does not

    require, as in this example, that the same number of points be

    input provided that the chordwise node cards for each sectionhave a non-zero value for NPC, the numbez of panels chordwise,

    and that this is repeated at each spanwise station.

    3.1.4 Rotors--Type-4 Patches

    In the body/rotor analysis, two models of the rotor areconstructed. They are the detailed blade element model which is

    to be discussed later and the panel model which provides the

    coupling between the rotor and fuselage flow fields. The panelmodel of the rotor is constructed in much the same way as the

    bodies of rotation discussed above with the added fact that the

    chordwise and spanwise (in the rotor framework radial and azi-muthal) panel breakdown forms the basis for the radial spacing ofblade stations and the azimuthal increments in the blade element

    calculation.

    The rotor is modelled using a disc-like array of panels

    generated in exactly the same way as the bodies of revolution.The panels are represented, as are all panels in program VSAERO,

    by a combination of source and doublet singularities. In a type-4 patch both source and doublet elements of the singularity are

    specified (known as a result of the blade element calculation)and are passed over, within the program, from the blade element

    to the panel calculation. Part I of this reporu contains an ex-planation of the form of the singularities. Each rotor disc mustform a separate patch preceded by the appropriate parch card and

    it is recommended that they also be identified as a separate

    component for ease of manipulation and the separate accumulationof loads. Figure 8(a) and (b) shows how a typical main rotor may

    be generated.

    The input for this example, Figure 8(b), begins with a patchcard with IDENT set to four (4) to signify a rotor. This is

    followed by the section card, placing the rotor center in th_

    global frame with the appropriate values of STX, STY and STZ andannouncing that a body of revolution is to be generated with?_ODES--3, -4 or -5. Using this approach, INMODE is most commonly

    two (2) and the line defining the rotor disc is input in the y -

    0_0 plane with values of x and z and rotated about the x-axis(default). It is at this stage that blade coning can be intro-

    duced., as in the example. With this simple form only two points

    are required, but, of course, any higher-order description may beused to generate curved rotor disc surfaces. In the example, the

    point closest to the axis forms the innermost defining station

    for the aerodynamic parts of the blade and the outer point thetip radius. Normally the blade radius is broken down

    24

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  • automatically specifying, as in the example, the inner and outer

    points and the number and distribution of panels to be formed onthe chordwise (radial) node card. INTC-2 is recommended for the

    radial breakdown since this concentrates the panels at the outer

    end of the radius. The number of panels is dictated by the

    detail required. Cases have been successfully executed with as

    few and 3 panels radially and the maximum set by program capacity

    is 20. Experience with conventional rotor performance programshas shown that fifteen segments radially is more than adequatefor detailed blade studies.

    Since the disc is being formed by the body of revolution

    feature, the number of azimuth stations is set by the NPS pa-rameter on the section card and the distribution should be uni-

    form with INTS set equal to three (3). The input is completed by

    including the rotation angle range of 3600.

    With the disc panelled in the input location about the x-axis, all that remains is to pitch it into the appropriate atti--

    rude. This is accomplished using the rotations available on thecomponent card. The default rotation is about the component y-axis with a positive rotation being nose-up. In the example, it

    was determined that the tip path plane should be 50 nose-down sothe rotation required on the component card to place the disc inthe correction orientation was +850. The values of the component

    origin, CTX, etc. then locate the rotor relative to the rest ofthe configuration

    If a more involved rotation was required, say to apply some

    lateral tilt to a main rotor or to position a tail rotor, thls

    can be done by activating the option to specify the axis of

    rotation. This is done by setting the scale parameter on the

    component card to a negative value and inserting on the followingcard two points specifying the rotation axis. The details for

    applying this technique are discussed in full in the VSAEROprogram guide and are summarised in Figure 9(a) and (b) for thecase of a tail rotor. Here, as a further example of the program

    flexibility, the rotor is input with unit radius and the scale

    parameter on the component card is used to bring the radius up tothe full scale value. A further point to note in the tail rotor

    model is that the rotation angle range has been changed to: 02 .

    450.0__ = 90.0. This is required to line up the first panel inthe pane_ model of the rotor with the zero azimuth location inthe blade element model. Since this is conventionally over the

    tall for the main rotor and along the aft pointing horizcntalradial for a tail rotor, the tall rotor panel model before rota-

    tion must start in the horizontal position. The same effect

    could, of course, be achieved by using INMODE-3 or 4, carrying

    out the original line definition in the z - 0 plane and by

    returning to the %2 " 360.0, 81 " 0.0 degrees rotation range.

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  • I

  • 4.0 WAKE INPUT

    4.1 Wake Gri_ Planes:- CARD SETS 17 and 18

    In program VSAERO the development of the wakes after they

    are shed is calculated in a series of planes perpendicular to the

    onset flow starting upstream of the first shedding location. Theway in which these planes are set up is described in full in the

    VSAERO program guide and the recommendations made there fOE fixed

    wing aircraft and general shapes apply equally well to rotor/bodyproblems.

    Figure 10(a) illustrates how the defining grid planes wouldbe set up for a typical helicopter study. Note that the first

    grid plane corresponds to the leading edge of the disc. As aeneral guide for isolated rotors, the grid planes should beistributed over the disc to correspond to the azimuthal break-

    down of panels using a full cosine distribution (dense at

    leading- and trailing-edges, open in the center) with steps equalto half of the total rotor azimuthal increments. Downstream of

    the trailing edge of the disc, the first two disc diameters of

    distance could be broken into ten segments with half cosinespacing and then a further six diameters with four large segmentsto fill in the fan-field effects.

    In regions _here substantial flow distortion is expected,

    say around the front of a fuselage or if details of the passage

    of a wake over a wing leading edge are required, then regions ofmore closely set grid planes are required. Figure 10(b) is an

    example of how this may be achieved.

    As with the input of body sections, the wake stations are

    specified by inputting a series of values separated with nodecards which indicate how intervals are to be divided up. Thenumber of divisions may be specified using NPC; the distribution

    is specified as with body input using the parameter, iNTC, and as

    before, individual stations may be input and used without furthersubdivision by setting NPC equal to zero. The last wake grid

    plane should be followed by a node card with NODE set equal to

    three (3) to terminate wake grid plane input.

    4.2 Separation Line Specification:- CARD SETS 19 _ 23

    In the version of program VSAERO described in this report,two types of wake are available. These are the type-I wakes,

    springing from lifting bodies, and the type-4 wakes, enclosingregions of flow with energy states higher or lower than the

    surroundings. The way in which these wakes are described aregenerally similar, the attachment process is identical and they

    only differ in that for the type-4 wakes the velocity jump across

    the jet sheet must be identified in order that the p_ogram mayassign the correct vortex strength to the sheet elements.

    3O

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    31

    ORIG4_AI., PAOB fliOF POOR QUALIT_

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  • While the uses of the type-i wakes are clear cut, on wingand other lifting-surface trailing edges, the use of type-4 wakes

    requires some additional explanation for the helicopter applica-tion. Several elements of helicopter configurations shed wakeswhere changes in energy level are involved. Most obvious is the

    efflux from the powerplant. Less clear, but nonetheless impor-

    tant, is the wake from the rotor head assembly. Since, in thiscase, the shape is normally not modelled in detail and the drag

    coefficient of the assembly is generally known, it is possible to

    model the overall effect of the component by constructing a bulkmodel and attaching a type-4 wake along its aft facing edges.

    The rotor model also uses a type-4 wake.

    Each individually identified wake is treated in much the

    same way as a patch is handled in the body input and, as in the

    case of the patch, it must be preceded hy a wake (patch) card,CARD 19. This card contains the information which identifies the

    wake type, IDENTW-I for a regular wake or -4 for a jetmodel/separated base/roto: wake; indicates whether the wake is

    held fixed or is relaxed, IFLEXW-I or 0, respectively; and a

    descriptive title.

    4.2.1 Wake Definition for TvDe-i Wakes

    The method of attaching the wake along the separation line

    is explained in detail in the VSAERO Program User's Guide. Thefollowing notes should be considered a supplement to the origi-nal, more detailed presentation.

    The separation line is applied to the surface in such a waythat the local attached flow comes from the left. In the example

    shown in Figure ii the separation is parallel to side 2 of the

    patch. The string of panels to which the wake sheet is attachedis identified on Card 20 as follows.

    (KWPACH) (KWSIDE) (KWLINE) (KWPANI) (KWPAN2) (INPUT) (NODEWS)

    1 2 0 1 6 2 0

    (or 0) (or 0)

    Default for the set

    of panels alongsideKW._IDE

    Dsing the default, 0, forKWPANI, KWPAN2 in cases

    where the string of panela

    is the complete set parallelto side KWSIDE is recommended

    KWPACH is the patch to which the wake is attached and KWSIDE the

    patch side parallel to and in the same direction as the shedding

    line. If the sheet is attached along the patch edge, KWLINEtakes the default value of zero. However, if the sheet were

    attached along an internal panel edge, this would be identified

    by counting, in this case along side 1, until the shedding panel

    33

  • ORI_INAI_ PAQE I1iOE POORQUAU'I_

    S DE /./(FIRST SECTION INPUTT_

    3

    FLOWDIRECTION

    SIDE 1

    SEPARATION LINE

    WAKE LINE 1

    INPUT WAKE LINES

    WAKE-SHEDDING PANELS

    (TO THE LEFT OF THE SEPARATION

    LINE)

    "-- WAKE LINE 2

    PROGRAMGENERATES

    IMMEDIATE LINES

    BY LINEAR

    INTERPOLATION

    "I Figure ii. Type-i Wake-Wing Separation Lines.

    34

  • was _eached. This number, then, defines KWLINE. KWPANI and 2

    define the spanwise extent of the shedding; again the default

    values of zero give full span, and numbering proceeds across the

    patch in the direction of the shedding line where only part-spanshedding is present. Card 20 is equivalent to the section card,

    Card Ii, of the body input.

    Because INPUT is 2 on card 20 above, this card must be

    followed by CARD SET 21/22 defining the _eometry of streamwise

    wake-line, LINE i. As with the input of body section data, thewakes may be prescribed in a number of ways. For the current

    example, INPUT-2 indicates that the program expects data to beentered in X and Z coordinates with a local origin at the shed-ding point. As with the body input, wake filaments may be des-

    cribed with any level of detail desired and the wake segmented

    with node cards separating the different elements. For thesimple case used here, if an initially rectilinear wake was

    required, it should be enough to prescribe a point in the farfield downstream and a node card. If the wake had to pass anobstruction, say another body or a flap, a more detailed path may

    be prescribed. Both examples are outlined in Figure 12 below.

    In both cases the X and Z coordinates are relative to an originat the trailing edge. CARD SET 21/22 is equivalent to CARD SET

    12/14 of the body input.

    When the input is complete the wake is terminated withanother CARD 20:

    (INPUT) (NODEWS)

    0 0 0 0 0 0 3

    The string of wake-shedding panels

    has already been defined

    This copies LINE 1 to LINE 2 to

    complete the wake geometry des-cription. (Note that INPUT>0can be used here if a differen_

    wake line geometry is required,in which case CARD SET 21/22 mustfollow foc LINE 2)

    End of this wakebut another wakemust follow. The

    final wakehave a 5 here

    Note: In the case of type-i wakes (IDENTWsl on CARD 19) it is

    possible to turn the wake over and attach it along side 4 of thepatch--in this case it would start at the tip and move inboard.CARD 20 would then be:

    35

  • ORIGINAI_ PA_3_ I_

    OE POOR QLIAUTY

    SIMPLE WAKE

    LAST WAKE GRID PLANE

    o

    INPUT POINT

    .uu,. :? _f2,:,,2,9

    SWPZA

    MORE COMPLEX WAKE

    REGION 2

    WAKE 1 I

    WAKE 2 -'-"

    • INPLFI_ POINTS

    (H:.',='" "-:[email protected]

    _-00 f'" [O0 CC:

    ].ZO:': .C" " .-'O :'_'

    [,_O0 CO _:OO C:_'

    -_20'."

  • (KWPACH) (KWSIDE) (KWLINE)

    1 4 0

    ORIGINAL PAGE I$

    oF. POOR QUALII_

    (KWPANI) (KWPAN2) (INPUT) (NODEWS)

    1 7 2 0

    (or 0) (or 0)

    No change

    In the initial example, the wake input at the first section was

    simply copied across the span, but in many cases this would beinappropriate. A more involved example is given below.

    Changing the wake line geomtry in the middle of a patch isachieved by simply breaking the string of wake shedding panels

    into sets. This is possible since there is an opportunity todefine a streamwise wake line at the beginning of each string of

    wake-shedding panels and at the end of the last string• This is

    explained by Figure 13. The input for these wakes would be asfollows

    IDENTW

    CARD 19 1 0 0 Wing Wake

    CARD 20 1 2 0 1 5 2 0

    CARD SET 21/22

    for Line 1

    CARD 20

    CARD 20

    SWPX(1) , SWPZ (i)

    SPWX(2), SWPZ(2)

    1 2 0

    INPUT=2 Format

    (NODEWS) (NWP) (INTC)

    3 I0 3

    6 6

    KWPANI, KWPAN2

    1 2 0 7 12

    0 0

    INPUT -0

    Copies Line 1into Line 2

    2INPUT for

    Line 3

    37

  • ORIGINAE PAGiE15OE POOR QUALITY

    alI II II,I

    @®TOP VIEW

    7

    !

    ' i I ,

    I ' i--" 'l i -_ LOCAL-

    ._-8 9 i 10 i]] i.'l_ OF, SEQUENCEI PANELS COUNTED

    ALONGI SEPA_TION

    I LINE

    II

    I STREAMWI SEWAKE LINES

    (_ DEFINED ININPUT

    C

    SIDE VIEW

    1

    __ __._-- ----"-- LINE (_-'_'_"___ -- 3 LINE (_

    • INPUT POINTS _'- _ _ LINES (_) AND [email protected]

    3 " LINES (_ AND @

    (SECOND WAKE)

    Figure 13. Wake Shedding Schematic--Multi-line Input.

    38

  • CARD SET 21/22

    For Line 3

    CARD 20

    SWPX (i) , SWPZ (i)

    SWPX(2), SWPZ(2?

    (NODEWC) (NWP) (INTC)

    3 i0 3

    0 0 0 0 0 2 3NODEWSs3terminates

    this wake

    _t

    .j

    I

    CARD SET 21/22

    for Line 4

    CARD 19

    CARD 20

    CARD SET 21/22

    for Line 5

    SWPX (i) , SWPZ (i)

    SWPX(2), SWPZ(2)

    e •

    1 0

    2 2

    SWPX(1), SWPZ(1)

    SWPX(2), SWPZ(2)

    (NODEWC) (NWP) (INTC)3 i0 3

    0 Flap Wake

    0 0 0 2 0

    (NODEWC) (NWP) (INTC)3 10 3

    CARD 2 0 0 0 0 0 0

    INPUT-0 Copies Line

    5 (i.e., the previousline) into Line 6

    0

    NODEWSs5

    for final

    wake

    5

    !

    P

    i

    If the wake separation line passes over a number of patches then

    a separate string of wake-shedding panels must be specified foreach patch. (Multiple strings of wake-shedding panels may stillbe specified within a patch as shown above)• This is illustrated

    3g

  • with the example shown in Figure 14. Following the sketch, the

    multipatch input for this wake becomes:

    KWPACH K'_SIDE KWLINE KWPANI KWPAN2 INPUT NODEWS

    CARD 20 1 2 0 0 0 2 0

    CARD SET 21/22 FOR WAKE LINE 1

    CARD 20 2 2 0

    CARD 20 3 1 0

    0 0 0 0

    (Copies wake line 1 intowake line 2)

    5 6 2 0

    CARD SET 21/22 FOR WAKE LINE 3

    CARD 20 3 2 0 0 0 2 0

    CARD SET 21/22 FOR WAKE LINE 4

    CARD 20 0 0 0 0 0 2 5

    End of Wake Input

    CARD SET 21/22 FOR WAKE LINE 5

    _ARNING: Before leaving the discussion of type-i wakes, it is

    important to note that the panelling on the upper and lower sidesof the wake mus_ match. This is required so that the correct

    doublet jump across the wake may be properly evaluated and shedinto the wake columns.

    4O

    L_ __.;_ xj

  • PATCH 2OmC,_IAI: PA(W !_OF. POOR _UALITY

    PATCH 1

    PATCH 3

    SIDE i

    !

    /IiII0WAKE LINES

    SIDE 2

    SIDE 2

    SIDE 3

    III®

    Figure 14. Multiple Patch Wakes.

    41

  • 4.2.2 Wake Definition for Type-4 Wakes on Bodies

    Type-4 wakes are specified in the same manner as type-i

    wakes, and are fed by flow from the left when looking along thedirection of the separation line. Figure 15 shows two examples

    of this type of wake.

    In the jet efflux case, Figure 15(a), the nacelle and base

    are all part of the same patch and the wake is attached along the

    aft-facing edge. This is parallel to side 2 of the patch on the17th row of panels along side 1 (see Figure 5 for details of

    nacelle panelling). Consequently, KWPATCH takes the nacellepatch number, KWSIDE-2 and KWLINE-17. Since the wake is attachedacross the full width of the patch, KWPAN1 and KWPAN2 are set tozero,

    In the case of the rotor head block model, Figure 15(b), the

    block is in three parts with separate patches for the front and

    rear faces, patches 1 and 3, and the main surface as patch 2.Here, the wake is attached along the edge, side 3, of patch 2.

    Consequently, KWSIDE-3, KWLINE-0 (the default for the edge) andKWPANI and KWPAN2 are again zero, since the wake goes all aroundthe edge of the patch.

    The wake geometry for type-4 wakes is defined in a manner

    identical to that required for type-i patches on CARD SETS 21/22.

    Since type-4 patches involve regions of higher or lowerenergy and the wake strength is set to produce the appropriateinternal flow, the inner and outer velocities (normalized with

    respect to a unit onset flow) must be specified. This is done on

    CARD SET 23 immediately following the wake definition.

    Input for normal type-4 wakes (i.e., those attached tonormal wing or body patches) is completed by ensuring that the

    flow into the wake cavity, from the area of panels enclosed bythe wake, matches the flow down the inside of the wake column.

    This is done by using the option available within the program to

    suspend the usual assumption of zero flow through the boundaryand by replacing it with appropriate normal velocity. This wouldbe positive for an outflow. The special options available with

    CARD SET 8 provide this capability.

    The first entry on Card 8, NORSET, sets the number of

    regions in which the transpiration velocity is to be changed. If

    this is non-zero, the program then expects to read a Card 8A foreach region. Explained in detail in the VSAERO manual, Card 8A,

    identifies the patch and the rows and columns involved, and

    specifies the lelocity value. Examples are given of typical CARDSET 8/8A input for the two cases in Figure 15.

    42

  • • \

    ORIGIINAL PAGE li

    OF, POOR QUALITY

    PANEL NUMBERS

    COUNI_ ALONGSIDE 1

    _S IDE 1

    NACELLE BASE

    PARALLEL TO SIDE 2

    SEPARATION

    PANELS TO LEFT

    OF SEPARATION LINE

    KWSIDE=2; KWLINE=17

    KWPAN1 AND KWPAN2 = 0

    CARD 8

    (NORSET NVORT NPSOM JETPAN)

    1 0 0 0

    CARD 8A

    (NORPCH NORF NORL

    1 18 i

    NOCF NOCL VNORM)

    0 0 2.5

    DEFAULT FULL WIDTH (TYPICAL)

    Figure 15(a) . Type-4 Wake on Nacelle.

    43

  • PAQE I_

    OE POOR QUALITY

    F; 3

    FLOW

    KWPATCH=)

    KWSIDE:5 __

    _LI NE=O _._..kSVPAN1AND _PAN2 = 0 "

    CARD 8:

    (I_ORSET NVORT ETC.)1 0

    CARD 8A:

    (NORPCH

    3

    Figure 15(b).

    NORF

    0NORL NOCF NOCL VNORM)

    0 0 0 0,0

    DEFAULT FULL PATCH TYPICAL

    Type-4 Separated Wake on Block Model of Rotor Head.

    44

  • CARD SET 8/8A is also used to identify sets of panels which

    are known to fall inside £egions of higher/lower energy level.

    This is required if correction of the calculated values of the

    pressure coefficients to account for the altered dynamic head of

    the region is desired. As with the outflow option above, the

    number of sets of panels to be modified are identified with

    JETPAN on CARD 8 and the patch row and column information sup-

    plied on CARD 8A for each set. The incremental dynamic head is

    calculated with the wake sheet values of VIN and VOUT input onCARD 23.

    4.2.3 Wake Definition for Type-4 W_';_

    The wakes used in the rotor calculation are a special

    form of the type-4 wakes discussed above and are invoked by the

    program automatically when a type-4 wake is attached to a type-4

    rotor patch. Wake attachment is similar to that described for

    other type-4 patches above, but extra care must be taken to

    completely enclose the wake volume. This is detailed in Figure16.

    Considering how the rotor patch is generated by rotating the

    input section, the chordwise (in this case radial) direction is

    side 1 of the _atch. The outer edge of the disc becomes thespanwise directlon and is side 2 of the patch. Side 3 and side 4

    follow naturally to complete the definition. The card set forthe wake is as follows.

    (IDENTW) (IFLEXW) (IDEFW) (WNAME)

    CARD 19 4 0 0 ROTOR WAKE TIP

    Type-4 Wake

    Distorted wake

    will be calculated

    Separation line

    definedby panel

    string, Card 20

    must follow

    CARD 20

    (KWPATCH)(KWSIDE) (KWLINE) (KWPANI)(KWPAN2) (INPUT) (NODE}'G)

    1 2 0 0 0 2 0

    Tip circle Default

    attaches Default attaches

    wake along wake along the

    patch edge full length of edge

    45

  • ORIGINAK PAGE. I_

    OF, I_OOR QUALITY .- .-

    TIP ___ SIDE 2 .. .- /'

    _ '"\ ii I _CONNECTING SHEET

    ROOT SEPARATIONPANELS

    £,

    Figure 16. Rotor Wake Specification--Simple Isolated Rotor.

    46

    )

  • CARD SET 21/22: DEFINING WAKE FILAMENT AS IN TYPE-I WAKES ABOVE.

    CARD 20

    (KWPATCH)(KWSIDE)(KWLINE) (KWPAN1) (KWPAN2)(INPUT) (NODEWS)0 0 0 0 0 0 3

    terminates

    copies filament input tip wakeon previous CARD 20 to

    close wake column

    (IDENTW IFLEXW IDEFW) (WNP_E)

    CARD 19 4 0 0 Rotor Wake Root

    CARD 20

    (KWPATCH) (KWSIDE) (KWLINE) (KWPANI) (KWPAN2) (INPUT) (NODEWS)1 4 0 0 0 2 0

    CARD SET 21/22: TO DEFINE WAKE LINES

    CARD 20

    (KWPATCH) (KWSIDE) (KWLiNE) (KWPAN1) (KWPAN2) (INPUT) (NODEWS)

    0 0 0 0 0 0 3Terminates root

    vortex

    (ID ENTW IFLEXW IDE FW) (WNA ME )

    CARD 19 1 0 0 Connecting Sheet

    CARD 20

    Note type-i wake

    for connecting sheet

    (KWPATCH) (KWSIDE) (KWLINE) (KWPANI) (KWPAN2) (INPUT) (NODEWS)1 3 0 0 0 2 0

    CARD SET 21/22: TO DEFINE WAKE LINES

    CARD 20

    (KWPATCH) (KWSIDE) (KWLINE)(KWPAN1) (KWPAN2)(INPUT)(NODEWS)

    0 0 0 0 0 0 5Last Wake

    Input

    47

  • This example shows the simplest form of rotor wake input and

    provides an initially prescribed skewed cylinder form for the

    wake tube generated by copying the first filament input around

    the edges of the patch. This is adequate for cases where no body

    is in close proximity to the rotor. For cases where the fuselage

    presents substantial interference, a more involved wake

    specification is required. An example of this is provided in

    Figure 17 and below. The technique is identical to that

    illustrated above for type-i wakes varying in a spanwise

    direction. For the example, the rotor disc has been divided into

    16 azimuthal sections (columns). Although the analysis in

    program VSAERO can cope with an initially prescribed wake

    filament passing through a body, it is better from the point of

    view of numerical stability if all filaments are prescribed so

    as to pass over the outside. In the situation pictured in

    Figure 17, the fuselage is narrow relative to the disc panelling

    and only the three filaments from the front of the disc, fromcolumns 8, 9 and I0, need to be bent to pass around the body. In

    the illustration, filament 1 is copied around the edge to fila-

    ment 7. Filaments 8, 9 and i0 are input individually. Filament

    ii is a return to the original trajectory and this is copied

    around until the wake closes at filament 17. The data set for

    this looks as follows. It should be noted that the filament is

    associated with the trailing corner of the panel in questions

    (corner 2 in the example shown).

    (KWPATCH) (KWSIDE) (KWLINE) (KWPANI) (KWPAN2) (INPUT) (NODEWS)

    CARD SET 20 1 2 0 1 6 2 0

    Attachment to Input as

    columns 1-6 X and Z

    CARD SET 21/22: WAKE FILAMENT INPUT AS X AND Z RELATIVE TO SHED-

    DING POINT FOR FILAMENTS 1 TO 6 AND TO BE COPIED

    TO 7.

    CARD SET 20 1 2 0 7 7 0 0

    Last section of Copies

    "constant" wake previoussection

    CARD SET 20 1

    CARD SET 21/22:

    2 0 8 8 2,3 or 4 0

    Filament 8 Input as

    required

    WAKE FILAMENT INPUT AS X,Z OR X,Y OR X,Z AS

    NEEDED FOR FILAMENT 8.

    48

  • ORIG_iAL PA(m

    oF. POORQu,_.r_

    TIP-EDGEP&

    LINE 8

    LINE 9

    LINE i DEFINED :

    FUSELAGE

    INPUT WAKE LINES

    COPIED WAKE LINES

    NOTE: FOLLOW SAME PROCEDUREFOR ROOT WAKE LINES,

    LINE 17 (CLOSE 16)COPIED

    \

    -k

    _ - SIDE 2

    ___ S._EwPAA__K_A____IION_L IDE

    SIDE 1

    TYPICAL TIP-EDGESHEDDING PANEL

    Figure 17. Rotor Wake Input Schematic with Fuselage Present.

    49

    )

  • CARD SET 29 1

    CARD SET 21/22:

    2 0

    FOR FILAMENT 9

    9 9 2,3 or 4 0

    CARD SET 20 1

    CARD SET 21/22:

    2 0

    FOR FILAMENT i0.

    i0 I0 2,3 or 4 0

    CARD SET 20 1

    CARD SET 21/22:

    CARD SET 20 0

    2 0 Ii 16

    FOR FILAMENTS ii THROUGH 16.

    MENTS 1 THROUGH 7.

    0 0 0 0

    2 0

    SHOULD MATCH FILA-

    0 0

    Copies 16 to 17and closes outside

    of wake

    Wake definition continues with the input along sides 3 and 4

    of the patch displacing the wake filament as appropriate to passaround obstructions.

    Since rotor wakes are type-4 wakes, the initial wake

    strength must be defined with CARD SET 23, specifying VINNE R and" This is updated internally as the calculation proceeds.

    IKe conventional type-4 wake situations, there is no need to

    use NORVEL (on CARD 8) for rotor patches since the disc panelboundary conditions are set internally using local loadings sup-plied by the rotor blade element calculation.

    In a conventional VSAERO data deck, the wake data completes

    the Input string required for the aerodynamics calculation.However, if any type-4 rotor patches have been called, the

    program expects to read the input data set for the rotor bladeelmement calculation. This is described in the next section.

    L t

    5O

    !

    ._--p. ,,.-_ ,,. .... -

  • 5.0 ROTOR BLADE ELEMENT MODEL INPUT DESCRIPTION

    When the presence of a rotor is signalled by the insertion

    of a type-4 patch, the program requires that the data be loadedto construct the blade element model. This data set identifies

    the body patch involved; contains the controls which limit printvolume and iteration cycles; pzovides the description of the

    blade geometry and mass properties including twist, planform andairfoil section; and defines the flight conditions.

    5.1 Rotor Patch Identifiers (Cards R1 and R2)

    Since the blade element model is built on the framework

    provided by the panel model, with disc panels and blade segmentsbeing matched, the first data items identify the rotor patch.

    CA[D SET R1 provides the patch number and orients the disc forthe blade element velocity components. The parameter roll is therelative angle of rotor, zero degrees for a main rotor and ninety

    degrees for a tail rotor. The roll angle is used simply to

    resolve the induced velocity components generated in the bodyaxis system into the correct relation for the blade element

    analysis. Card R2 provides a general title for the rotor calcu-lation.

    5.2 Output Print Controls (Card R3)

    As an aid in rotor performance diagnosis, different levels

    of printout are available. At the most detailed level, all ofthe blade section geometric onset flow and loading data are

    available at each radial and azimuthal station for every step inthe iteration cycle. This includes in the first group, avail-able at every radius and azimuth:

    blade section radius, span, chord, geometric pitch, angle ofattack, yaw angle, inflow angle, Mach number, velocity

    components in rotor control axis system, induced velocity

    components in body axis system, section lift coefficient,and section drag coefficient.

    The second group includes the loading data available every radiusand azimuth. These are:

    blade loading (lift/unit span), H-force loading, total

    torque loading, drag torque loading, lift torque loading,

    segment lift, segment H-force, segment total torque, lifttorque, and drag torque.

    The third group includes integrated blade data available ateach azimuth location. This is made up of principally blade

    lift, H-force and torques and includes the blade flapping

    parameters, the flapping angle and the first and second flappingderivatives.

    51

  • Rotor totals are printed for each iteration and are not

    selectable.

    The output data selection is completed with an option to

    print the airfoil data as input and as interpolated at inter-mediate stations. It is recommended that restraint be exercised

    in switching on the print options since large volumes of output

    are generated. Irrespective of the print option chosen, the plotfile contains all of the data for the final iteration cycle. The

    printout default values are all OFF &nd a particular group of

    output must be selected by inputting a value of one for theparameter. Card R3 is arranged in columns of i0 as outlinedbelow.

    ISPNTI IS PNT2 IB PNTI IPT1 IPT2

    Card 3 0 or 1 0 or 1 0 or 1 0 or 1 0 or 1

    Group 1 Group 2 Group 3 Airfoil Data

    Blade section data

    at every radius andazimuth

    Blade totals

    at eachazimuth

    5.3 Iteration Controls. (Card R4)

    The rotor model used in the delivered verison of the program

    is for a fully articulated rotor and the performance calculationmay proceed in either of two modes. In the first, direct mode,

    the blade control angles are preset and the calculation goes one

    cycle. In the second mode the rotor forces and moments arerequested and the controls adjusted through three embedded itera-

    tion loops to produce the desired levels. The parameters entered

    on Card R4 control this process. These parameters, with MCOUNTcontrolling rotor moments, LCOUNT controlling rotor lift, and

    NFLAP controlling blade flapping, and hence control axis orienta-tion, may be set individually or together using default values.

    5.3.1 Blade FIaDDinu

    The innermost iteration is the blade flapping cycle

    which steps the blade around the azimuth calculating the loadsbased on t_e local conditions and the blade response to condi-

    tions at the previous step. The blade is assumed to be fully

    articulated. The default value of the controlling _rameter is 4(four full azimuthal cycles allowed to stabilize apping). If

    the blade flapping cycle is inhibited, by setting NFLAP-I the

    blade flapping parameters, the control axis angle and the fore,aft and lateral flapping inputs must be included on Card RII.

    Even if the default flapping cycle is selected, NFLAP-0 (set to 4

    52

    t

  • internally), it speeds convergence if values of control and

    flapping angles are set on Card RII.

    5.3.2

    The rotor lift is modulated using the collective pitch

    control. A total of six iterations are permitted if the default,

    LCOUNT-0 (set to 6 internally) are used. A starting value of

    collective pitch must be entered on CARd RII. The search for a

    converged value of collective pitch uses a quadratic fit throughthe successively updated calculated thrust values, comparing ateach step with the target value. Blade flapping equilibrium is

    re-established after each change in collective pitch.

    5.3.3 Rotor Moments

    The rotor pitching and rolling moment loop entered on

    Card R4 produces the default, three iterations. If a search isordered, target values of pitching and rolling moment must beloaded on Card RI3 or zeroes will be assumed. If MCOUNT is set

    equal to I, values of lateral and fore and aft cyclic pitch mustbe input on Card RI2.

    5.4 _ Element Model Geometry (CARD SETS R6, R7, R8,Rg, R10)

    In the program the basis for the blade geometry and break-

    down into radial sections comes from the panel model. Havingidentified the appropriate patch, the panel corner points on the

    first column of the patch are studied (by the program). At thesame time the number of rows (bla_e segments) is set, NR, and thenumber and size of the azimuthal increments determined, NC, from

    the number of columns on the patch. The panel geometry isavailable at this stage as coordinates in the global axis system.

    To convert these into blade radii requires the input of the rotor

    center of rotation and this is supplied on Card R5. The paneledges become the radial boundaries between the blade sections and

    the disc panelling and blade segmentation correspond. These

    radii form the basis for the rest of the @eometr_ input data.Figure 18 illustrates how this procedure Is carrled out. Thefirst radial station, defined by the innermost panel edge, is

    assumed to be coincident with the flapping hinge for the articu-lated rotors modelled here. The rest of the blade geometzy

    information is input at the blade radial stations corresponding

    to the panel edges.

    Blade geometry is defined with three parameters entered on

    CARD SETS R6, R7 and R8. These, respectively, are the chord, the

    twist and the leading-edge sweep. Each card set contains two

    53

    J_

  • o_ poor __

    \

    RADIAL AND AZIMUTHAL

    •"_DISTRIBUTION SET BY__ i _"VSAERO" PANEL MODEL

    - I PUT

    DISC PANELLING

    DETERMINES BLADE""../I MODEL AZIMUTHAL

    INCREMENTS

    CARD SET 11

    l

    AFT

    VIEW FROM ABOVE

    _r (TYPICAL)

    BLADE SEGMENTATION

    FOLLOWS DISC PANELLING

    Figure 18. Schematic Relationship between Blade andPanel Models.

    54

  • basic parts. They are: first, a card containing an indicator,INSET, which signals if a constant value is to be read (INSET=I)or if values are to be read at the NR+I defininq radial stations(INSET=0). If a constant twist is selected, the total twist

    should be loaded defined in the conventional sense relative to

    the 0.75 radius.

    The rotor description is completed by entering the blade

    mass distribution, required by the flapping calculation on CardR9 and the number of blades on RI0.

    5.5 Rotor Pelfor_ance and Control.(Cards Rll, RI2, RI3, RI4)

    Cards RII through RI4 provide the input which set up andcontrol the r_or performance.

    5.5.1 Rotor Speed and Flapping. (Card RII)

    Card RII provides the information which orients the

    control axis system in space, sets up the initial flapping,applies a starting value of collective pitch and sets up the

    correct onset flow and rotor rotational speed.

    If the default, zero, value for the control axis angle,

    ALPHAC, is used here, the program requires that system drag (the

    negative of the rotor propulsive force required) be loaded inCard R13. Since the program calculates the blade coning from the

    input mass properties, entry of the blade flapping values, A1 andBI, completes the rotor orientation input. If the flapping is

    constrained, NFLAP-I on Card R4, appropriate values of AIPHAC, A1and BI, must be input. Otherwise, the calculation may be started

    assuming zero flapping, but supplying realistic starting valuesspeeds the flapping convergence. Input of unrealistic values of

    ALPHAC, A1 and B1 can lead to failure to close the flapping loop

    and a subsequent crash.

    Blade speeds are set with the input of the advance ratio,

    the rotor rotation rate, OMEGA, and the hover tip Mach number.

    5.5.2 Rotor Blade Cvcllq Control. (Card RI2)

    As was noted above in Section 5.3.3 in the discussion

    of Card R4, the user has the option, with the parameter, MCOUNT,of trimming the rotor to target moments (MCOUNT=0, default) or of

    setting cyclic controls and taking whatever moments result

    (MCOUNT-I). If MCOUNT is set equal to i, values of a and bmust be entered on Card RI2 or values of zero will be assumed.

    55

  • 5.5.3 Rotor Loads and Moments. (Cards RI3 and RI4)

    Rotor lift and moment targets and the aircraft drag areentered on Card RI3. If either LCOUNT or MCOUNT on Card R4 are

    left to the default value or if any value other than 1 is input,then target values of lift or moment must be loaded on Card RI3.

    The value of drag entered here is the drag area formed by

    dividing the actual drag by the dynamic pressure and is used as a

    guide in setting up the control axis angle if this is not inputabove on Card RII.

    Card RI3 is completed with the entry of VCLIM B in areaswhere it is derived.

    The air density used in the reduction of the loads and

    moments to coefficient form is entered on Card 14. If desired, arotor tip loss factor may be used in the calculation. This is

    also entered on Card RI4. When a tip loss is used, the lift

    outboard of the radius ratio, r/rTI P entered on Card RI4 isvaried linearly to zero at the tip. The calculated drag is notaffected.

    5.5.4 Airfoil Data Sets. (Card RI5, CARD SETS RI6)

    Airfoil data is used by the program in the conventional

    manner with table look-up and interpolation for C L and Cn as afunction of local aerodynamic angle of attack and Mach number.The airfoil sets are keyed to a @articular radius, specified atinput, and during execution the program interpolates between thedata sets appropriate to the nearest radial stations on eitherside of the blade segment radius.

    At input the parameter, NDSEC, on Card RI5 indicates how

    many data sets are to be loaded. Data sets may be loaded or

    copied from sets loaded earlier in the input string. This is

    indicated by a parameter on the first card of set RI6. With theparameter, ICOPY-I, a data set is read. With ICOPY-0 the data

    set is copied form the previously read set. The radius (abso-lute) at which the data applies is also entered on Card RI6.1.

    The data set follows using the "standard" C81 format, Ref. 2. In

    this format data is read as a function of blade section angle ofattack for a range of Mach number. Each set of coefficients is

    entered separately. The program interpolates to the local coef-ficient value at the required value of Mach number and angle of

    attack and then between data sets, loaded as a function of spanlocation, to the correct value.

    56

    O

  • 6.0 INPUT DATA DECK BLOCKING AND VARIABLE LIST

    The VSAERO data deck assembly was described in great detail

    in the user's document and will not be repeated here since the

    only change in set-up from the operational point of view is theaddition of the rotor data block. This enters the run stream

    after the wake information has been loaded.

    6.1 Input Summary

    The input is divided into the following parts:

    (i) BASIC INPUT

    General information, operating mode, onsetflow, reference conditions, special options

    (ii) PATCH GEOMETRY

    Description of configuration surface in com-

    ponents, patches, sections, basic points,etc., for panel generation

    (iii) WAKE INPUT

    Wake-grid-planes, type of wake, wake separa-tion line, initial streamwise geometry

    (r) ROTOR INPUT

    Geometry, iteration and print controls,control settings, force and moment targets,and airfoil data

    (iv) SURFACE STREAMLINE INPUT

    Location of starting point for each surfacestreamline

    (v) BOUNDARY LAYER INPUT

    Reynold's nmaber, etc.

    (iv) OFF-BODY STREAMLINE INPUT

    Location of starting point and required up-stream/downstream distances for each off-

    body streamline

    In the following description, the input variables are first

    listed in 6.2 for each of the above parts. Then, 6.3 gives adetailed description of the function of each input variable.This is followed in 6.4 by an input flow chart to help with the

    assembly of the input data file. Section numbering has been leftcommon with the original VSAERO document. In the detailed des-cription and flow chart sections, only the rotor input is des-

    cribed. The user is referred to the Program VSAERO User's Guide

    for the other sections.

    57

  • 6.2 Input Variable List

    Basic Input Summary

    1

    2

    2A

    3

    3A

    4(a)

    or4(b)

    4A

    Text

    IPRI, IPRLEV, IPRESS, MSTOP, MSTART, MODIFY

    IPRGOM, IPRNAB, IPRWAK, IPRCPV, IPRPPI (onlyif IPRLEV-5 on CARD 2)

    MODE, NPNMAX, NRBMAX, ITGSMX, IMERGE, NSUB,NSPMAX, NPCMAX

    NROWB(1), I-l, INRBMAXI (only if NREMAX0 and IBLTYP-0 on CARD 4(a)

    (i) NPSETS

    (ii) NPCHBL, NBCOL, (KOL(1), I-l, NBCOL)(Number of 4A(ii) cards - NPSETS)

    If HSTART>0 and MODIFY-0; this is the end of

    the basic data on a restart run.

    7

    8

    6A

    RSYM, RGPR, RNF, RFF, RCORE, SOLRES, TOL

    ALDEG, YAWDEG, RMACH, VMOD, COMFAC

    ALBAR, RFREQU, HX, HY, HZ (only if MODE-2 onCARD 3)

    CBAR, SREF, SSPAN, RMPX, RMPY, RMPZ

    NORSET, NVORT, NPASUM, JETPAN, NBCHGE

    58

    Zo/m

    20A4

    615

    515

    815

    16!5

    315

    215

    I5

    1615

    7FI0.0

    5FI0.0

    5FI0.0

    6F10.0

    515

  • Car_ Noo

    8A (NORPCH(1), NORF(I), NORL(I), NOCF(I),

    NOCL(I), VNORM(I), ADUB(I), I_1, NORSET)(only if NORSET>0 on CARD 8)

    8B (i) VORT

    (ii) (RXV(I), RYV(I), RZV(I),I=l, NVORT+I)

    (only if NVORT>0on CARD 8)

    8C (NPSPCH(I), NPSRF(I), NPSRL(I), NPSCF(I),NPSCL(I), I-l, NPASUM) (only if NPASUM>0 onCARD 8)

    8D (JETPCH(I), JETRF(I), JETRL(I), JETCF(I),JETCL(I), VINCI), VOUT(I), I-1, JETPAN)

    (only if JETPAN>0 ON CARD 8)

    8E (KPAN(I), KSIDE(I), NEWNAB(I), NEWSID(I), I-l,

    NBCHGE) (only if NBCHGE>0 on CARD 8)

    Format

    515,2F10.0

    F10.0

    3F10.0

    515

    5152F10.0

    415

    patch Geometry Input Summary

    9

    9A

    10

    11

    CTX, CTY, CTZ, SCAL, THET (component card)

    CPX, CPY, CPZ, CHX, CHY, CHZ (only if SCAL

  • Card Noe

    12(a)

    (b)

    (c)

    (d)

    (e)

    if)

    (g)

    13

    BY, BZ, X (INMODE=I)

    BX, BZ, Y (INMODE=2)

    BX, BY Z (INMODE=3)

    BX, BY, BZ (INMODE-4)

    TC, INPUT (INMODE-5 or 7)

    H, INPUT (INMODEI6 or 8)

    BX, RAD, THET (INMODE=I2)

    XRB, NINT (after options 12(e) and 12(f)

    14

    15

    16

    NODEC, NPC, INTC, MOVE (use with CARD 12 andand 137

    14A NPCH, NSEC, IB, LB (if NODEC

  • J

    _o

    21 (a) SWPY, SWPZ,

    21(b) SWPX, SWPZ,

    21(c) SWPX, SWPY,

    _les

    X (if INPUT--I on CARD 20)

    Y (if INPUT--2 ON CARD 20)

    Z (if INPUT,.3 on CARD 20)

    21(d) SWPX, SWPY, SWPZ (if INPUT=4 on CARD 20)

    22 NODEWC, NPC, INTC

    23 VIN, VOUT ... (if IDENTW..4 on CARD 19)

    R2

    R3

    R4

    R5

    R6 .i

    R6.2

    R7 .i

    R7.2

    RS.I

    R8.2

    R9

    R10

    Rotor Input Summary

    IPRCH, ROLL

    TITLE

    ISPNTI, ISPNT2, IBPNTI, IPTI IPT2

    MCOUNT, LCOUNT, NFLAP

    XO, YO, ZO

    INSET

    CHORD(I), I'l for INSET--I

    I-NR+I for INSET-0

    INSET

    TWRATE, for INSET--I

    TWIST(I), I-NR+I for INSET-0

    INSET

    SWEEP(1), I-i for INSET--II-NR+I for INSET-0

    BMASS

    NB

    61

    30X,315

    8FI0.0

    Format

    If0,FI0.0

    80AI

    8II0

    3Ii0

    3FI0.0

    If0

    8FI0.0

    If0

    FI0.0

    8F10.0

    If0

    F10.0

    8F10.0

    FIO.O

    IlO

    )

  • Card Noe

    RII

    RI2

    RI3

    RI4

    RI5

    RI6 .i

    RI6.2

    RI6.3

    R16.4

    R16.5

    MU, ALPHAC, OMEGA, MTIP, COLL, AI, B1

    ALPHAS (Not used), AIS, BIS

    BW, DRAG, PM, RM, VCLIMB

    RHO, TIPLOS

    NDSEC

    ICOPY, YR

    TITLE, (NMACH(I), NALPHA(I), I=i,2 )

    MACH(J) , J=l, NMACH

    ALPHAI, (COI(I,J), J=l,9)

    (COI (J) , J=10, NALPHA)

    Repeat R16.4 AND R16.5 NMACH times

    Repeat to R16.3 twice COI(I,J)=CL, I=l,

    CD' I=2

    Repeat to RI6.! N_SZC times

    8FI0.0

    8FI0.0

    8FI0.0

    8FI0.0

    ]_i0

    I10,FI0.0

    8FIO.O

    8_i0.0

    8FIO.O

    Repeat Rotor Card Set R1 - RI6 for each type-4 patch.

    Surface Streamline Input Summary

    24

    25

    F, KP, NS (compulsory input if IBLTYP-I)(Place one card no. 24 for each streamline)

    F, KP, NS (end of surface strem-niine data)

    FI0.4,215

    2FI0-4,215

    62

    I

  • Card N_e

    26

    Bcundary Layer Input Summary

    RNB, TRIPUP, TRIPOP, XPRINT, XSKIP

    (CARD 26 only present if NVPI>0 on CARD 4(a))

    Format

    5FI0.0

    27

    28

    29

    29A

    _O

    30A

    31

    31A

    32

    33

    34

    34A

    34B

    34C

    Off-Body Velocity Scan InDut Summary

    ymzia t

    MOLD, MEET, NEAR, INCPRI, INCPRJ, INCPRK

    (Start of each scan box. Finish the set with

    a blank card)

    XO, YO, ZO, NP (if MOLD=I on CARD 27)

    XI, YI, Zl, NPI (if NP>I on CARD 28)

    (ALI(I), I=l, INPII) (only if NPI2 on CARD 28)

    (AL2(1), I=l, INP21) (only if NP2

  • Off-Body Streamline Input Summary

    Card Noo

    35

    Y_lLinnle_

    RSX, RSY, RSZ, SU, SD, DELS, NEAR

    (one card per streamline_ finish with a blankcard)

    Format

    6FI0.0,I5

    64

  • R1

    6.3 Rotor Input Data Deck Description

    Note: All integers are right justified.

    I-i0

    Rotor patch number

    11-20 ROLLRotor roll attitude=0.0 for main rotor

    - 90.0 for tail rotor

    If0

    FI0.0

    R2 1-80 TITLE 80AI

    r_

    .P

    R3 i-i0

    11-20

    21-30

    31-40

    L%RR21

    =i, prints blade radial varia-

    tion of blade section data

    =0, suppresses print

    =I, prints blade radial varia-tion of blade loads, etc.

    -0, suppresses print

    -I, Prints rotor forces and

    moment summary at each azimuth

    -0, suppresses print

    J2.tt

    -i, prints input airfoil data

    =0, suppresses print

    65

    If0

    If0

    If0

    Ii0

  • Card Columns

    41-50

    =I, prints interpolated airfoilat each blade section

    =0, suppresses print

    Format

    Ii0

    R4 i-i0

    Controls cyclic pitch/rotor

    moment loop

    =0, sets default =3

    =i, runs tc set values of Als andBls

    If0

    ii-20

    21-30

    LCOUNT

    Controls collective pitch/rotor

    lift loop

    -0, sets default =6; recon_enddefault or 13

    NFLAP

    Controls blade flapping/tip path91ane loop

    =0, sets default _4; recommend -4for main rotors, =i for tail

    rotors

    If0

    Ii0

    i

    R5 1-30 xo. Y0. zo

    Rotor centeL' in body axis system

    3FI0.0

    66

  • r.

    Card

    R6 (SET)

    6.1

    6.2

    R7 (SET)

    R7.1

    R7.2

    R8 (SET)

    RS.I

    R8,2

    R9

    RI0

    Columns

    i-I0

    1-80

    i-I0

    1-80

    i-i0

    1-80

    i-i0

    I-i0

    Inset =-i, constant chord; read

    only 1 value on 6.2

    Inset =0, variable chord; read(NR+I) values on 6.2

    Blade chord values, dimensions infeet

    Inset 5-1, constant twist rate; read

    total twist from 7.2

    Inset 50, variable twist; read (NR+I)values on 7.2

    Blade twist values

    Inset 5-1, total twist in Col. i-i0

    Inset50, section twist relative to

    0.75 radius, in degrees

    BLADE LEADING-EDGE SWEEP

    Inset 5-1, constant sweep; 8.2

    blank (sweep 5 0.0)

    Inset 50, variable sweep; read(NR+I) values from 8.2

    S%Jep valuesInset 5-i, blank card

    Inset 50, leading-edge sweep

    positive aft in degrees

    Distribution assumed constant;

    dimensional in slugs/ft.

    NUSBER OF

    67

    Format

    If0

    8FI0.0

    IlO

    8FIO.O

    IlO

    8FI0.0

    FIO.O

    Ii0

  • Card

    RII

    i-I0

    11-20

    21-30

    31-40

    41-50

    51-60

    61-70

    ROTOR PARAMETERS

    ADVANCE RATIO

    CONTROL AXIS ORIENTATION

    =0 if drag value on Card 14 used

    = value if tip path tilt entered

    (degrees positive aft)

    rotor rotational speed (radians/sec.)

    HOVER TIP MACH NUMBER

    _NPUT COLLECTIVE PITCH (degrees)

    A1

    Sl

    Input fore and aft flapping

    (degrees)

    Input lateral flapping (AI andB1 can be input = 0.0)

    FI0.0

    FI0.0

    FI0.0

    FI0.0

    FI0.0

    FI0.0

    FI0.0

    RI2

    i-I0

    11-20

    21-30

    CYCLIC CONTROLS

    SHAFT AXIS ANGLE (not used)

    AIs

    Fore and aft cyclic input (deg.)

    sls

    Lateral cyclic input (deg.)

    FI0.0

    FI0.0

    68

  • RI3

    RI4

    hmaa

    i-i0

    11-20

    21-30

    31-40

    41-50

    i-i0

    11-20

    RI5 I-I0

    ROTOR LOADS AND MOMENT VALUES

    GROSS WEIGHT (ibs.)

    DRAG

    (D/q) square feet

    ROTOR PITCHING MOMENT TAR_

    (set MCOUNT=3 on Card 3)(ft.-ibs.)

    ROTOR ROLLING MOMENT TARGET

    (set MCOUNT-3 on Card 3)(ft.-ibs.)

    V CLIMB (ft./see.)

    MISCELLANEOUS

    (slugs/Ft.3)

    TIP LOSS FACTOR

    Linear tip loss applied outside

    input value, R/RTip

    Default =0.0, no tip loss

    NDSEC

    Number of airfoil data sets

    following

    Format

    FI0.0

    FIO.O

    FIO.O

    FI0.0

    FI0.0

    FIO.O

    I10

    RI6 AIRFOIL DATA SETS

    Repeat ND sec. times

    Note: Repeat R1 through RI6 for each rotor, type-4, patch used.

    69

  • J

    CARD SET RI6:- AERODYNAMIC SECTION DATA. These data tables are

    input in the standard format currently used in

    the Rotorcraft Flight Simulation Program, C-81,Ref. 2.

    Repeat NDSEC times.

    _t

    ii

    !

    CARD 16A:- CODV Control Inteaer.

    D uL u 2.Um

    1-5 ICOPY(IDSEC) 0 Complete aerodynamic tables are readin for this section

    ID Sectional aerodynamic data is copied

    over from previously defined sectionID

    Note: If ICOPY(IDSEC)>0, the rest of CARD SET RI6 is omitted for

    this section.

    CARD RI6B:- Title @nd Control Card.

    columns

    1-30 TITLE ANY Alphanumerical title of sets of tables

    31-32 NMACH (i) 3-18 Number of Mach number entries in C Ztable

    33-34

    35-36

    NALPHA (i) 3-99

    NMACH (2) 3-18

    Number of angle-of-attack entries inC tableZ

    Number of Mach number entries zn C dtable

    37-38

    39-40

    NALPHA (2) 3-99

    NMACH (3) 3-18

    Number of angle-of-attack entries in

    C d table

    Number of Mach number entries _n C

    table. Not used. Set=0 m

    41-42 NALPHA (3) 3-99 Number of angle-of-attack entrles inC table. Not used. Set-0m

    7O

    )

  • NOte: CARD SETS RI6C through RI6E are repeated as a group three

    times for C£, C d and Cm; that is, in the following des-criptions

    K = 1 C Z

    K = 2 C d

    K - 3 Cm

    Not used in rotor/body performancecalculation at this time

    CARD 16C:- Mach Number Entries•

    nluaam

    8-14

    15-21

    22-28

    64-70

    Note:

    Value

    MACH (I) arbitrary

    MACH (2)

    MACH (3 )

    MACH (9 )

    % UzutQn

    Lowest Mach number

    Next highest Mach number

    Next highest Mach number

    Next Highest Mach number

    Additional card may be required with same format to inputNMACH(K) values of Mach numbers•

    CARD RI6D:- Anule-of-Attack/Coefficient Data.

    Columns

    1-7

    8-14

    15-20

    22-28

    value

    ALPHA(K) arbitrary Angle of attack, degrees

    COI (K,I)

    COI (K,2)

    COI (K,3)

    Coefficient at MACH(1)

    Coefficient at MACH(2)

    Coefficient at MACH(3)

    64-70 COI (K,9) Coefficient at MACH(9)

    71

  • CARD RI6E:- Continued Coefficient Data.

    c hu=m

    8-14

    64-70

    Value

    COI(K,10) arbitrary

    COI (K,18)

    Coefficient at MACH(10)

    Coefficient at MACH(18)

    Notes: i. CARD RI6E included only if NMACH(K)>9.

    2. CARDS RI6D and RI6E repeated NALPHA(K) times for each

    angle of